1. Field of the Invention
This invention relates to a medical device, and more particularly, it is concerned with a medical instrument used for administering to or receiving from medical fluid, for example, syringes, transfusers (introducer), operation devices for blood gathering or blood transfusion, mechanical parts, etc.
2. Description of the Prior Art
As to the medical instruments, the varieties, performances, qualities and standards of instruments or machines are provided in the Drugs, Cosmetics and Medical Instruments Act. In this age of rapid progress of medical techniques, instruments or machines having more excellent performances than such standard values or standard items have appeared.
As a soft elastic material for a medical instrument, there is mainly used natural rubber (NR), but at the present time, isoprene rubber (IR), butyl rubber (IIR), halogenated butyl rubbers (BIIR, CIIR), nitrile rubber (NBR), styrenebutadiene rubber (BR) have widely been used in view of that these rubbers are more sanitary and have more excellent properties.
As to a synthetic resin, polyethylene (PE), polyvinyl chloride (PVC) and polypropylene (PP) have been authorized by the Japanese Pharmacopoeia of 8th Revision and applied to a number of medical instruments or machine parts.
PVC seems to be a clear and soft sanitary article, but detailed examination thereof tells a problem that a plasticizer such as dioctyl phthalate, dioctyl adipate (DOA) and tricresyl phosphate (TCP) or a stabilizer such as zinc stearate, calcium stearate and tin compounds is dissolved out in a medical fluid. The use of PVC in the future is questionable because of a problem on protection of environment such that raw material monomers of PVC remain and poisonous gases are generated when used instruments are burnt up as a waste. On the other hand, a number of studies have been made on a medical instrument for preservation of blood (Japanese Patent Publication No. 42507/1990, Japanese Patent Laid-Open Publication No. 212536/1990).
Lately, PE has widely been used, since a gas sterilization method of ethylene oxide or formaldehyde is authorized and is sanitarily excellent. In particular, ultrahigh molecular weight polyethylene is relatively excellent in softening point (130.degree. C.) and laminated articles thereof with a vulcanized rubber, PP, nylon, PVC, etc. has being authorized. However, PE has a large disadvantage that the softening point is low.
PP has a large feature of its high softening point, but because of difficulty in obtaining a transparent article, it has been proposed to modify PP to give a transparent article which can be applied to medical instruments or pharmaceutical agents (Japanese Patent Laid-Open Publication Nos. 163144/1991 28246/1991).
Polyvinylidene chloride is generally blended with PVC to form an article because of difficulty in molding an article of polyvinylidene chloride.
Fluoro resins are excellent in sanitary property, heat resistance, acid resistance, alkali resistance, etc., but are so inferior in adhesiveness and in workability that these resins cannot be applied to parts for widely used medical instruments.
In addition, nylons, polycarbonates, polyurethanes, polyethylene terephthalates, ethylene vinyl acetate copolymers, polystyrenes, acrylic resins, thermoplastic elastomers, etc. are resins each having various properties, but having many problems from the standpoint of a raw material for a medical instrument and having no property to substitute for PE or PP.
The present invention has been made under the situation to develop an article for a medical instrument using a novel material capable of dosing a patient with a medical fluid in a very sanitary manner.